Cardiopulmonary resuscitation (CPR) administered by a bystander is a life-saving intervention for individuals having a cardiac arrest outside the hospital. While we know that cardiac arrest rates vary widely across cities, what about the differences among neighborhoods in the same area?

Researchers examined data from the Cardiac Arrest Registry to Enhance Survival (CARES) by census track over three years for Fulton County, Georgia, an area that includes Atlanta. The registry links data from 911 callers, EMS providers and receiving hospitals. The 161 census tracks served as an approximation for neighborhoods.

The researchers found that the frequency of cardiac arrests varied from neighborhood to neighborhood (from .04 to 2.11 per 1,000 persons), yet were consistent within a neighborhood year-to-year. The mean number of cardiac arrests per year was 2.21 but 25 of the neighborhoods had twice that number in one or more of the three years studied; seven had at least six arrests in two of the three years. The frequency of bystander CPR also varied by neighborhood (from 0% to 100%), with a mean rate of 25 percent.